Test 3: Wk 11: 8 Neural Control of Breathing - Puri

Question 1

Dyspnea is the feeling of

Answer 1

being short of breath, or the unpleasant conscious

awareness of difficulty in breathing.

Question 2

when arterial PaO2 falls or PaCO2 rises from breath holding, asphyxia,
or pulmonary disease, dyspnea leads to

Answer 2

efforts to increase ventilation and thus to restore arterial blood gas levels to normal

Question 3

What causes dyspnea when blood gasses are normal

Answer 3

increased airway resistance

Question 4

mechanical event for inspiration

Answer 4

contraction of diaphragm

Question 5

neural event for inspiration

Answer 5

firing of phrenic motoneurons

Question 6

where are phrenic motor neurons located

Answer 6

within the ventral horn of the cervical spinal cord c3-c5

Question 7

mechanical event for expiration

Answer 7

relaxation of diaphragm and recoil of lungs

Question 8

neural event for expiration

Answer 8

phrenic motoneurons stop firing

Question 9

rate of respiration is dependent on

Answer 9

the interval between bursts of phrenic nerve action potentials

Question 10

tidal volume is determined by

Answer 10

the strength of the diaphragm contraction which is determined by the number of phrenic motor units recruited

Question 11

— controls the act of breathing

Answer 11

the medullary pattern generator

Question 12

below level IV

Answer 12

all breathing stops

Question 13

Below level I

Answer 13

all breathing intact

Question 14

cut at level III (btwn pons and medulla)

Answer 14

tidal volume increased and apneustic breathing starts

Question 15

Dorsal Respiratory Group (DRG are — neurons in the —

Answer 15

Inspiratory neurons in the ventrolateral nucleus of the tractus solitarius (NTS)

Question 16

The tractus solitarius project primarily to the — for —

Answer 16

contralateral phrenic motoneurons for passive inspiration and expiration

Question 17

expiratory neurons in the nuclease retroambigualis

Answer 17

Ventral Respiratory Group (VRG)

Question 18

the nucleus retroambigualis project to — and — for —

Answer 18

contralaterally to abdominal and intercostal muscles.

Primarily for forced expiration

Question 19

Bötzinger and Pre-Bötzinger complexes contain

Answer 19

pacemaker cells

for automatic generation of respiratory rhythm

Question 20

Inspiratory “Ramp” Signal:

Answer 20

The nervous signal that is transmitted to the inspiratory

muscles, mainly the diaphragm via the phrenic nerve

Question 21

how does ramp signal work

Answer 21

not an instantaneous burst of action potentials. Instead, it begins weakly and increases steadily in a ramp manner for about 2 seconds in normal respiration. Then it ceases abruptly for approximately the next 3 seconds, which turns off the excitation of the diaphragm and allows elastic recoil of the lungs and the chest wall to cause expiration.

Question 22

advantage of ramp signal

Answer 22

causes a steady increase in the volume of

the lungs during inspiration, rather than inspiratory gasps

Question 23

The — controls the “switch-off” point of the inspiratory ramp, thus
controlling the duration of the filling phase of the lung cycle.

Answer 23

pneumotaxic center

Question 24

The function of the pneumotaxic center is primarily —

Answer 24

to limit inspiration

Question 25

apneustic breathing

Answer 25

prolonged inspiratory efforts interrupted by

occasional expirations

Question 26

opiates inhibit

Answer 26

the central pattern generator

Question 27

opiates and benzos cause

Answer 27

respiratory depression

Question 28

Excitatory amino acids, —, activated — receptors

Answer 28

glutamate, NMDA

Question 29

Inhibitory neurotransmitters include — and —

Answer 29

glycine and γ-aminobutyric acid (GABA)

Question 30

Benzodiazepines exert their
effect by binding directly to — increasing the inhibitory effect
of —

Answer 30

GABAA

endogenous GABA.

Question 31

Peripheral chemoreceptors activate the CPG via

Answer 31

glutamate-releasing neurons.

Question 32

Central chemoreceptors activate the CPG via

Answer 32

acetylcholine-releasing neurons.

Question 33

peripheral chemoreceptors located in

Answer 33

carotid bodies and aortic bodies

Question 34

Peripheral chemoreceptors carotid bodies afferent pathway

Answer 34

Glossopharyngeal Nerve CN IX

Question 35

Peripheral Chemoreceptor aortic bodies afferent pathway

Answer 35

Vagus Nerve CN X

Question 36

peripheral chemoreceptors are exposed to

Answer 36

arterial blood

Question 37

peripheral chemoreceptors respond to (3)

Answer 37

⬇ PaO2
⬆ PaCO2
⬇ pH

Question 38

peripheral chemoreceptors pH detected by — only

Answer 38

carotid

Question 39

central chemoreceptors location

Answer 39

ventrolateral medulla near exits of CN IX and X

Question 40

central chemoreceptors chemical stimuli

Answer 40

increased medullary extracellular and CSF H+ resulting from ⬆ PaCO2

Question 41

central chemoreceptors are not stimulated by

Answer 41

decreased PO2 (hypoxia)

Question 42

central chemoreceptors respond to changes in — H+ concentration

Answer 42

CSF

Question 43

— ions directly activated central chemoreceptors

Answer 43

H+

Question 44

— does not directly act on central chemoreceptors

Answer 44

CO2

Question 45

normal drive for ventilation during acute hypercapnia

Answer 45

increased PaCO2

Question 46

— are acute regulators of day to day breathing and respond to changes in —

Answer 46

central chemoreceptors

CO2

Question 47

defect in central chemoreceptors

Answer 47

they “reset” if changes in CO2 are prolonged, like baroreceptors

Question 48

shift in sensitivity to PaCO2 is exaggerated in

Answer 48

metabolic acidosis

Question 49

Chemical control of breathing in pts with chronic hypercapnia

Answer 49

central chemoreceptors adapt to prolonged elevated PaCO2 and are no longer the central regulator
pts with COPD have decreased O2 which will activate peripheral chemoreceptors

Question 50

the main stimulus to breathe in chronic hypercapnia is

Answer 50

Hypoxic Drive

Question 51

oxygen induced hypoventilation

Answer 51

administration of high concentrations of O2 to a person with chronic hypercapnia will increased their Pa)2 and knock out their hypoxic drive

Question 52

for hypoxic drive to kick in PaO2 must drop below

Answer 52

60mmHg

Question 53

when PaO2 decreases to threshold levels the ventilatory response is mediated solely by

Answer 53

carotid chemoreceptors

Question 54

— does not stimulate the central chemoreceptors

Answer 54

decreased PaO2

Question 55

synergistic effect on ventilation when

Answer 55

increased PaCO2 accompanies decreased PaO2

Question 56

pulmonary stretch receptors act to

Answer 56

terminate inspiration and decrease respiratory rate by increasing expiratory time

Question 57

Hering-Breuer Inflation Reflex mediated by

Answer 57

impulses traveling in the vagus nerve

Question 58

Hering-Breuer Inflation Reflex originates in slowly adapting stretch receptors located within

Answer 58

smooth muscle of large bronchi and small bronchioles

Question 59

most stretch receptors fire during

Answer 59

tidal breathing

Question 60

deep breaths — Liter(s) are sufficiently large enough to trigger stretch reflex

Answer 60

1 liter

Question 61

Activation of rapidly adapting receptors in the trachea cause

Answer 61

cough, bronchoconstriction, and mucus secretion